Marcel Duchamp placed a urinal in a gallery and called it art. Decades later, in a series of afternoon conversations in his New York apartment, he explained exactly what he meant — and why the artist, in the end, doesn't count.

By 1964, Marcel Duchamp had been famous for almost fifty years and had spent much of that time carefully avoiding the obligations that fame imposes. He had largely stopped making art in the conventional sense. He played chess. He gave occasional interviews. He watched, with evident amusement, as the art world he had quietly detonated continued to process the blast.

Calvin Tomkins caught him in that mood — reflective, sardonic, generous, and entirely without reverence for the institution he had done more than anyone to destabilise. The Afternoon Interviews transcribes a series of conversations recorded in Duchamp's New York apartment, and what makes them remarkable is not what they reveal about art history but what they reveal about a particular cast of mind: one that found rigid systems inherently comic, that distrusted beauty as a criterion, and that located the most interesting territory in art precisely where definition broke down.

Duchamp's central target was what he called retinal art — work that appealed primarily to the eye, that delivered its effect through visual pleasure and stopped there. This had been the dominant mode since the Renaissance, and Duchamp found it limiting because visual beauty had become the only criterion. Art that asked nothing of the mind, that resolved itself entirely in the looking, was, for him, a missed opportunity. "Anything systematized becomes sterile very soon," he tells Tomkins — and the history of Western art, as Duchamp read it, was a long process of systematisation interrupted by occasional acts of genuine disruption.

His own disruptions are now canonical, which would probably have amused him. The readymades — a urinal, a bicycle wheel, a bottle rack, objects selected, neither made nor transformed, and placed in contexts that forced the question of what made something art — were not, he insists, attempts to find hidden beauty in everyday objects. That interpretation, however flattering, misses the point. "I never intended to sell my readymades," he says. Their purpose was conceptual, almost philosophical: to demonstrate that the designation of an object as art was an act of thought, not of craft, and that the boundary between art and non-art was therefore a matter of decision rather than essence.

This leads to the idea that runs through the interviews like a current: the role of the viewer. For Duchamp, the artwork is not complete when the artist finishes it. It is barely begun. "The artist produces nothing until the onlooker has said, 'You have produced something marvelous.'" The viewer is not a passive recipient but an active co-creator, bringing their own interpretive framework to a work and, in doing so, adding a layer of meaning the artist could not have anticipated or controlled. This is why, for Duchamp, "the artist doesn't count" — not as a gesture of false modesty, but as a precise statement about how meaning is made. Once a work enters the world, it belongs to whoever encounters it. The artist's intention is one reading among many, and not necessarily the most interesting one.

There is a filmmaker who arrived at a remarkably similar position by completely different means. Chris Marker's Sans Soleil (1983) is a film that resists almost every convention of documentary: it has no stable narrator, no linear argument, no fixed point of view. It weaves footage from Japan, Guinea-Bissau, Iceland, and San Francisco into a meditation on memory, time, and the impossibility of capturing experience in images — while simultaneously making images of extraordinary power.

Like Duchamp's readymades, it refuses to resolve. It places its materials in front of the viewer and leaves the act of completion to them. "He wrote me," the film's narrator says of its unnamed protagonist, "that in the nineteenth century mankind had come to terms with time, and that in the twentieth it was doing the same with space." The film is itself a demonstration of what happens when you trust the viewer to make sense of things — when you resist the systematisation that Duchamp identified as the enemy of genuine thought.

Together, Tomkins's interviews and Marker's film trace the outline of an idea that neither states directly: that the most alive works are the ones that remain permanently open, that meaning is not deposited in an object by its maker but generated in the encounter between the object and whoever meets it. For anyone working in fields where the relationship between maker and audience is constantly being renegotiated — which is to say, most fields — this feels less like art theory and more like a description of how anything meaningful actually works.